Distributed network systems have been widely adopted with the emergence of the cloud for computing applications. Network systems encompass numerous connected devices including servers, switches and other components. Traditionally, such devices have a number of fixed circuit boards, as well as other components such as cooling systems and power systems. However, the demand for flexibility as well as the need for upgrading components has increased as the use of network systems has increased. Recently, network devices have been based on a modular design having a chassis such as a rack assembly. The rack assembly includes certain components such as controllers, data and power interfaces. The rack assembly also includes slots for the installation of replaceable operation sleds that contain hardware components that may be connected to the rack assembly. The benefit is that the individual operation sleds with hardware components may be replaced or maintained without discarding other components of the network device. Network administrators benefit from the greater flexibility as they may upgrade or alter hardware without having to replace entire devices.
The hardware components in network devices generate heat during their operation, thereby requiring fan systems to cool the components during their operation. In the more modular devices, the operation sleds are inserted in slots that are held by the rack assembly. A central fan system such as a fan wall is installed on one end of the rack assembly to cool all of the sleds installed in the assembly. However, to replace or access an individual operation sled, the entire device must be powered down since the fan system must be removed to access the operation sleds. The fans cannot function when an individual sled is removed. Operating the device without the fan wall in place would result in overheating the components on the rest of the sleds.
FIG. 1 shows a typical prior art network computing device 10 such as a network switch that has a rack assembly 12 having a back side 14. The rack assembly 12 has side walls 16 and 18 and is enclosed by a front assembly 20 that holds line cards, fabric cards and other electronic switching equipment. The back side 14 is generally open to allow the mounting of multiple operation sleds such as operation sleds 22, 24, 26 and 28 held by the side walls 16 and 18. Each of the sleds 22, 24, 26 and 28 include various components such as boards including hardware such as processing cores and memory that are connected to the line cards and fabric cards on the front assembly 20. The heat generated from the components on the boards in each of the sleds 22, 24, 26 and 28 and the front assembly 20 is cooled by a fan wall 30 that holds a number of fans in proximity to the sleds 22, 24, 26 and 28. Typically, the fan wall 30 is mounted on the back side 14 of the device 10 after the operation sleds 22, 24, 26 and 28 are placed in the rack assembly 12.
The fan wall 30 is located in proximity to the inserted operation sleds 22, 24, 26 and 28 in order to provide a direct outlet for the hot air generated from the operation of the hardware components on each of the sleds 22, 24, 26 and 28. The fans in the fan wall 30 circulate this air out the back side 14 of the device 10. In order to replace or repair the sleds 22, 24, 26, 28 from the back of the rack assembly 12, the fan wall 30 must first be removed so an individual sled may be removed from the rack assembly 12. Since the fan wall 30 is thus rendered inoperative, the rest of the sleds cannot be operated during the removal of an individual sled. Thus, the operation of the device 10 must be interrupted to replace or maintain an individual sled.
Thus, there is a need for a system that includes a modular fan system that allows the operation of multiple sleds when a single sled is replaced. There is also a need for a modular fan system that allows the cooling of different components by allowing the removal of only one set of fans. There is a further need for fan modules that are individually attachable to and removable from operation sleds.